Atrophic Scars, Acne
Atrophic scars are the most ubiquitous type of scars, and are characterized by skin depressions caused by a loss of underlying supporting structure, such as collagen, fat or muscle. Various types of atrophic scars exist, secondary to conditions like trauma, inflammation or disease. The most frequently observed types of atrophic scars are those caused by common acne. Subcutaneous treatment of atrophic scars has the potential of elevating the sunken depressions, provided that an adequate subdermal pocket can be created, to be filled with either endogenous wound healing tissue or with injected or implanted material. Key to the creation of an adequate pocket is the dissection of fibrous strands or septae anchoring the skin in many atrophic scars to the underlying tissue. A surgical treatment sometimes used for the treatment of atrophic scars is Subcision®, in which a tri-beveled needle is repeatedly inserted into the subcutaneous space to cut subcutaneous tissue, specifically the fibrous septae, releasing the skin from its attachment to deeper structures. In a typical procedure the needle may be inserted many times, moving in fan-shape patterns radiating from its access site. This may be followed by a fan-like sweeping action, to ensure full detachment of the tissue layers. This procedure makes the method time consuming and prone to inadvertent deeper injury due to the large number of lancing movements with the needle. Additionally, in clinical practice, re-depression after an initially seemingly successful procedure is commonly observed. It is thought initially blood and extracellular fluid fill a pocket around the dissected needle tracks, that provides lift to the treated scar. When an inadequate pocket is created, resorption of the coagulated blood and fluids over time may cause the pocket to collapse, causing the late failure. Re-depression may also occur from reformation of scar tissue in response to the multiple planes of injury.
Wrinkles
Facial skin is unique because of its connections to the underlying Superficial Muscular Aponeurotic System (SMAS). The SMAS is a layer of musculature, responsible for facial expressions and is attached to facial skin through numerous fibrous septae. As a consequence, skin regions heavily involved in facial expressions are densely attached, and with progressing age such areas will start to show such expression lines known as wrinkles, crow's feet and laughing lines. Two approaches are commonly used in cosmetic surgery to improve the appearance of skin around and over these expression lines. One relies on subdermal tightening (Plication) of the SMAS, which tightens the overlying skin through the attachment septae, after which the excess skin is dissected. In this case the role of the septae is beneficial. The other approach employs fillers, like collagen or hyaluronic acid to bulk up the space below the skin. This approach by itself often results in unsatisfactory results, because of the fixed attachment of the skin to the underlying SMAS. In these cases, controlled severing of the fibrous septae may allow for a more effective use of the fillers to reduce the appearance of expression lines.
Subcutaneous Implants
Subcutaneous implants may be used for a variety of purposes. They include shape-enhancing implants used in cosmetic or reconstructive surgery and therapeutically used implants like subcutaneous venous access ports, battery packs for implanted electronic devices, implanted drug delivery devices and other implanted medical devices. Rapid and controllable creation of a subcutaneous pocket is a key component of the implantation procedure for such devices.
Wound Healing
Contractile scar formation can be a serious and sometimes debilitating side effect of wound healing. Tension within the plane of the skin at the site of the wound is generally considered a significant factor in the development of contractile scarring. In the presence of non-elastic fibrous septae connecting the dermis to the underlying subcutaneous tissue around a wound, tension from the suture used to close the wound may be highly localized at the site of the wound. The skin itself tends to be more elastic than the fibrous septae connecting it to the underlying tissue. Consequently, severing the fibrous septae may relieve the local stress, as the tension is distributed over a wider area of skin.
Liposuction
Cosmetic liposuction is one of the most commonly performed cosmetic surgical procedures. While the results are generally favorable, there is a certain percentage of patients where uneven subcutaneous fat distributions or skin irregularities are observed at the end of the healing period. Frequently, these are caused by the presence of fibrous septae connecting the skin to underlying subcutaneous tissue layers, and, occasionally, by the development of scar-like adhesions after liposuction surgery. Both of these phenomena may cause a lack of mobility which prevents the skin from assuming the desired smooth contour lines of the treated body parts. Additionally, secondary treatment procedures are sometimes performed, in which adipose tissue is moved or transplanted from areas with excess fat to areas with insufficient support for the overlying skin. The presence of scar-like adhesions or fibrous septae connecting the skin to underlying subcutaneous layers may interfere with a physician's ability to remove unwanted fat, or reposition such fat at desired locations. All these cases have in common the presence of unwanted connective tissue in a subcutaneous space. Traditional open cosmetic surgery would negate the advantages of the minimally invasive liposuction procedure, and a minimally invasive procedure to treat the unwanted connective tissue is needed to complement liposuction in these patients.
Hyperhidrosis
Hyperhidrosis is a condition characterized by an excessive production of sweat by echini sweat glands, specifically in the armpits, hands and feet. Eccrine sweat glands are mostly located in a relatively narrow tissue region underneath the dermis and are innervated by branches of the sympathetic nerve system. Current treatments range from the use of prescription strength aluminium chloride (anti-persiprant) and botulin injection, to surgery, including sweat gland extraction and thoracic sympathectomy, in which a branch of the sympathetic nerve system is severed. Sweat gland extraction may be time consuming and labor-intensive, while significant side effects of thoracic sympathectomy have been reported.
In all these cases, there is a need for a device and a method that enable an efficient performance of subcutaneous corrective surgery, capable of creating a subcutaneous dissection plane, severing certain target anatomical structures and, where necessary, providing a tissue pocket for further corrective procedures.